Advances in Earth Science ›› 2005, Vol. 20 ›› Issue (6): 618-626. doi: 10.11867/j.issn.1001-8166.2005.06.0618

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HE Juan; WANG Pinxian   

  1. Laboratory of Marine Geology, Tongji University, Shanghai 200092, China
  • Received:2004-06-07 Revised:2005-02-07 Online:2005-06-25 Published:2005-06-25

HE Juan;WANG Pinxian. VEGETATION CHANGE IN LATE MIOCENE AND EVOLUTION OF PHOTOSYNTHESIS[J]. Advances in Earth Science, 2005, 20(6): 618-626.

Rubisco, an ancient photosynthetic enzyme of Archean origin, became increasingly inefficient with reduction of atmospheric CO2 levels in the later geological history. The remarkable expansion of C4 biomass in late Miocene was an adaptive evolution in photosynthesis, as C4 photosynthesis was more adaptive to the lower concentration of CO2, as well as to monsoonal climate with warmer temperature and seasonal aridity. Given the significant difference in carbon isotope between C3 and C4 plants, the δ13C of paleosols and mammalian tooth enamels was widely used as an indicator of proportions of C3 to C4 plants in vegetation. Since the discovery of the dramatic shift of δ13C in the late Miocene paleosol from Pakistan over 10 years ago, the expansion of C4 biomass then has become a matter of hot debate within the scientific community: whether it was caused by monsoon climate, decreasing atmospheric CO2 level, or aridification?Though it remains an enigma up to now, there are useful lessons to be drawn from a brief review of the story as presented in this paper.

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